1. Field of the Invention
The present invention relates to a cylinder deactivation system for a vehicle and a variable valve lift system using the same and, more particularly, to a cylinder deactivation system fabricated with an end pivot structure that can control two valves at the same time.
2. Description of Related Art
Recently, numerous techniques aimed at improving fuel efficiency of a gasoline vehicle using a variable valvetrain have been applied due to the increase in oil prices. A cylinder deactivation system, one of the numerous variable valvetrain techniques, is a technique that deactivates a portion of unnecessary cylinders according to the load of engine, thus reducing the pumping and the friction loss.
To efficiently apply a cylinder deactivation system, it is necessary to provide a device for completely eliminating the valve lifts of the respective deactivated cylinders and such a device should satisfy the following functions and requirements: (1) A change between a common cam and a zero lift cam should be practicable; (2) The change between the common cam and the zero lift cam should be completed within one cycle of engine; (3) There should not be imposed mechanical compulsions and excessive forces upon the valve change; (4) Strength and durability of proper levels should be provided; and (5) A valve clearance should be maintained.
Cylinder deactivation systems have been mass-produced and applied mainly to the large displacement engines, such as V8 or V6. However, existing systems can have a number of drawbacks. For example, some systems are suitable to the push rod type engine, but not applicable to an over head cam (OHC) type; rather, it has characterized properties to an over head valve (OHV) type. Other structures using sliding pin connections have a drawback in that if the oil pressure is applied to separate the sliding pin, a load occurs in the return spring of the opposite pin, thus causing a sliding-contact continuously. Another device for the swing arm type requires that a latching system should be established to the respective valves.